Mutational analysis of the roles of residues in Escherichia coli elongation factor Ts in the interaction with elongation factor Tu.
The crystal structure of the Escherichia coli elongation factor (EF)-Tu.Ts complex indicates that there are extensive contacts between EF-Tu and EF-Ts. To determine the importance of these contacts in the interaction between E. coli EF-Tu and EF-Ts, residues in EF-Ts at the interface of these two proteins were mutated. The binding constants governing the interaction of the resulting EF-Ts variants with E. coli EF-Tu were determined. The effects of these mutations on the ability of EF-Ts to stimulate GDP exchange with EF-Tu.GDP and on its ability to stimulate the activity of EF-Tu in polymerization were tested. The results indicate that Arg-12, Met-19, and Met-20 in the N-terminal domain of EF-Ts and His-147 and Lys-166 and/or His-167 in subdomain C of EF-Ts are crucial in the interaction between EF-Tu and EF-Ts. Lys-23, Val-234, Met-235, and the C-terminal helix h13 are less important. The binding constants of the EF-Ts variants governing their interactions with EF-Tu correlate well with their activities in stimulating GDP exchange with EF-Tu. Mutations prepared in EF-Tu indicate that His-19 and Gln-114 but not Glu-348 in EF-Tu are moderately important for its interaction with EF-Ts.
Zhang
Y
Y
Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA.
Yu
N J
NJ
Spremulli
L L
LL
D002384:Catalysis; D004926:Escherichia coli / Q000235:genetics*; D006153:Guanosine Diphosphate / Q000378:metabolism; D015394:Molecular Structure; D016296:Mutagenesis; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D010445:Peptide Elongation Factors; D011994:Recombinant Proteins; C023512:elongation factor Ts; D006153:Guanosine Diphosphate